Bug FAQMargined Carrion Beetle
Oiceoptoma noveboracense · Order: Coleoptera · Family: Staphylinidae
Also called: Carrion Beetle
Adults are about 13 to 15 mm long and have a dark brown to black center on the pronotum edged with bright orange-red margins. They live in deciduous forests, grasslands and fields across the northeastern United States to the Rockies and possibly as far south as Texas. Adults feed on carrion and fly larvae, are used in forensic estimates of post-mortem interval, produce one generation per year with spring mating and about 45 days from egg to adult, and are often seen paired in spring.
Source: Wikipedia
How to recognize it
The middle of the pronotum is dark brown to black and the outer edges are outlined in a bright orange-red color.
Source: Wikipedia
Size
Adults measure roughly 13 to 15 mm (about half an inch) in length.
Source: Wikipedia
Where it lives
They are most commonly found in deciduous forests, grasslands and fields.
Source: Wikipedia
What it eats
Adults feed on carrion and on fly larvae that are also on the carrion, and they are used to help estimate post-mortem intervals in forensic work.
Source: Wikipedia
Life cycle
The species has one generation per year; mating starts in spring and it takes about 45 days from mating to adult emergence.
Source: Wikipedia
When you see it
In spring, adults are often seen paired with males mounted on females.
Source: Wikipedia
Where it is found in the US
Recorded in 40 of 51 states and DC. Most records: Illinois, Pennsylvania, New York, Michigan, Virginia, Kansas, Tennessee, Wisconsin.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
What do Margined Carrion Beetles look like?
They are 13 to 15 mm long, with a dark brown to black center on the pronotum edged in bright orange-red.
Source: Wikipedia
Where are these beetles found?
They live in deciduous forests, grasslands and fields across the northeastern US to the Rockies and possibly down to Texas.
Source: Wikipedia
What do they eat?
Adults feed on carrion and on fly larvae that are also on the carrion.
Source: Wikipedia
When are they active?
Mating occurs in spring, and adults are often seen paired during that season.
Source: Wikipedia
Same family (Staphylinidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Oiceoptoma_noveboracense
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.